A099696 Consider the family of multigraphs enriched by the species of involutions. Sequence gives number of those multigraphs with n labeled edges.

1, 1, 4, 25, 244, 3380, 62133, 1440382, 40673705, 1364815169, 53415511305, 2402797049419, 122751622204827, 7051227704802797, 451598420376965588, 32013004761567761223, 2495936511077175475140, 212840593118800653411004, 19753575434503894710824531

Offset

0,3

References

G. Paquin, Dénombrement de multigraphes enrichis, Mémoire, Math. Dept., Univ. Québec à Montréal, 2004.

Links

Andrew Howroyd, Table of n, a(n) for n = 0..100

G. Paquin, Dénombrement de multigraphes enrichis, Mémoire, Math. Dept., Univ. Québec à Montréal, 2004. [Cached copy, with permission]

Formula

E.g.f.: B(R(x)) where B(x) is the e.g.f. of A014500 and 1 + R(x) is the e.g.f. of A000085. - Andrew Howroyd, Jan 12 2021

Prog

(PARI) \\ R(n) is A000085 as e.g.f.; EnrichedGnSeq defined in A098620.
R(n)={exp(x+x^2/2 + O(x*x^n))}
EnrichedGnSeq(R(20)) \\ Andrew Howroyd, Jan 12 2021

Crossrefs

Cf. A000085, A014500, A098620, A099697, A099698, A099699.

Sequence in context: A194569 A356000 A198058 * A345105 A220192 A220356

Adjacent sequences: A099693 A099694 A099695 * A099697 A099698 A099699

Keyword

nonn

Author

N. J. A. Sloane, Oct 26 2004

Extensions

Terms a(11) and beyond from Andrew Howroyd, Jan 12 2021

Status

approved